Kolthoff remained at the University of Utrecht as a lecturer in
electrochemistry and a researcher until 1927. During this time he authored or coauthored 270 papers and three books and promoted the concept of pH, which was not well understood at the time. He also conducted a lecture tour of the United States and Canada in 1924. These activities earned him an international reputation. Kolthoff's scientific approach to analysis is widely accepted today, but was rare in the early 1900s when his career began.
Teaching Kolthoff advised 51 doctoral students in chemistry at the University of Minnesota, including
Johannes F. Coetzee,
Herbert A. Laitinen,
James J. Lingane and
Ernest B. Sandell, and several other masters and bachelors students. •
Der Gebrauch von Farbenindikatoren (1922): Kolthoff's first published monograph. This book went through several German editions and was translated into English in 1926. It was later titled "Acid-Base Indicators" after being expanded in 1937 with C. Rosenblum as coauthor. •
Konduktometrische Titrationen (1924) and
Potentiometric Titrations (1926):Kolthoff began to use conductometry and poteniometry in 1918 and 1920, respectively, which led to these two monograms. Potentiometric Titrations was especially influential, not only in analytical chemistry, but in other fields as well. •
Massanalyse (two volumes in 1927 and 1928): A continuation of his fundamental studies of classical methods, it was translated and coauthored by N. H. Furman in 1928 under the title "Volumetric Analysis." It also appeared much later (1942–1958) in an expanded three-volume edition coauthored by V.A. Stenger, G. Matsuyama, and R. Belcher. •
The Colorimetric and Potentiometric Determination of pH (1931): This was Kolthoff's first book that was meant to be used as text for instruction. It was expanded with H. A. Laitinen in 1941 and released under the title "pH and Electrotitrations." •
Textbook of Quantitative Inorganic Analysis (1936): Co-authored by E. B. Sandell, this book presented fundamentals and experimental features of analysis, and was among Kolthoff's most influential textbooks. In 1969 it appeared under the new title "Quantitative Chemical Analysis," with contributions from Sandell, E. J. Meehan, and S. Bruckenstein as coauthors. •
Polarography (1941): Co-authored with James J. Lingane, this introduction to voltammetry was expanded in 1952 into two volumes. •
Emulsion Polymerization (1955): This book related to Kolthoff's work in synthetic rubber and his development of
cold rubber. It was coauthored with F.A. Bovey, A.I. Medalia, and E.J. Meehan. •
Treatise on Analytical Chemistry (first edition 1959): Co-published with
Philip J. Elving, this is Kolthoff's largest and most notable work. The volume is in three parts: "Theory and Practice" (11 volumes, published between 1959 and 1976), "Analytical Chemistry of Inorganic and Organic Compounds" (16 volumes, published between 1961 and 1980), and "Analytical Chemistry in Industry" (four volumes, completed in 1977) == Personal life and activism ==